Figure 5.
Patch-clamp analysis of Ca2+ requirements for TMEM16A activation by Eact and Fact. A) Apical membrane current measured in TMEM16A-expressing FRT cells. ER calcium stores were depleted by CPA (50 μM, 30 min) and 0 CaCl2 in bath. ATP (100 μM), Fact (10 μM), Eact (10 μM), and T16Ainh-A01 (10 μM) were added as indicated. B, C) Whole-cell TMEM16A currents were recorded at a holding potential at 0 mV, and pulsing to voltages between ± 80 mV (in steps of 20 mV) in the absence and presence of 3 μM Eact (B) or 10 μM Fact (C). Left panels: free calcium concentration of pipette solutions were clamped at 0 μM (black), 0.07 μM (green), 0.15 μM (red), and 1 μM (blue). Eact (3 μM) or Fact (10 μM) was added as indicated. Right panels: current-voltage (I/V) plots of mean currents at the middle of each voltage pulse. D) TMEM16A inhibited by 10 μM T16Ainh-A01 after stimulation by Eact or Fact.